Lost in Space: What Happens in the Black Hole, Stays in the Black Hole

Black holes are one of the most fascinating stellar objects known to mankind and today they form the confounding tether that unifies two of physics’ star products; quantum mechanics and general relativity.

Situated at the very edge of our knowledge of the scientific realm, black holes question the basis of fundamental theories of physics.

A black hole is formed from a dying star* (not all stars evolve into black holes) collapsing in on itself due to gravity. They first appeared as a sort of “edge case” while studying relativity, but now we have managed to even photograph one.

Source: Event Horizon Telescope (EHT) P.S. Your internet ain't slow ( unless it is ), the picture is like that. You will think I am fooling around but that's the best resolution we have so far. Why tho? This calls for a session of it's own!

*(a star needs to be more than roughly 3 times the size of our sun to qualify)

At the center of a black, gravity may be considered infinite. To be fair we can’t quite know what exactly happens inside a black hole, specifically what happens after you pass the event horizon. The event horizon is a boundary of a black hole, beyond which nothing which enters the black hole can escape it– not even light, a property alluded to by the object's rather menacing name and depictions.

As mind-bending as these objects are, they are still technically encapsulated by the predictions of our modern theory of General Relativity and Quantum Mechanics.

-Information Paradox has entered the chat

Well, it seems like black holes destroy information, which is a big no-no according to quantum mechanics.

But how does this happen?

Before we look into the black hole information paradox, we need to define what we mean by “information”.

In the context of the paradox, information about an object refers to the knowledge of the quantum mechanical state of the object (position, velocity, and spin). A quantum state of a system contains all “information” about the system. Quantum Mechanics implies that this information cannot be destroyed.

Got it? Cool.

So you take a Sunday morning stroll into a local black hole and poof, you vanish with all your information; you were last seen at the event horizon and everyone comes to the conclusion that the black hole ate you up. Too bad all information contained by you is lost to the outside world… BUT it may still be accessible inside the black hole. No information is destroyed… yet.

There is one more aspect left to discuss to come to the paradox; Hawking radiation.

Discovered by Stephen Hawking, this is the final piece to framing the paradox. Due to certain phenomena; the black hole is essentially forced to “produce” radiation constantly; this radiation cannot come without a cost somewhere else according to the law of conservation of energy– In this case, the energy is supplied by the black hole; And the black hole evaporates away at a very tiny rate as such. Given enough time it will completely vanish leaving only a stream of radiation as remnants. This forms our paradox. The information is lost!

There are many theories regarding the resolution of the information paradox, but none seem to complete the picture; at least not yet.

A popular view is one called Black Hole Complementarity (BHC)— in essence it states that no information from an object swallowed by a black hole is ever lost… if a “person” (external observer) were to “watch” the object gets swallowed, the physics at and near the horizon will be such that information is preserved by the way the radiation is emitted. BHC has been contested with the ‘firewall paradox’ which works by referring to the quantum entanglement of states involved.

Author: Madhav Prasad

Editor: Saatvik Sachdeva

Illustration: Sanskar Srivastava